Biomedical subjects

B E Alpert

Publications and source records attributed to B E Alpert.

9 recordsLinked to original sources

PubMed1994

Effects of CPAP on lung mechanics in infants with acquired tracheobronchomalacia.

Continuous positive airway pressure (CPAP) has been used in the treatment of infants with tracheobronchomalacia (TBM). However, the effects of CPAP on lung mechanics in these infants are unknown. We hypothesized that CPAP prevents airway collapse and improves forced exhalation. We studied respiratory mechanics of nine infants (age 15 +/- 3 mo, SEM) with acquired TBM documented by bronchoscopy, during quiet respiration and forced exhalation, using the esophageal balloon and rapid thoracic compression techniques, respectively. Measurements were made when infants received no CPAP and repeated when 5 and 8 cm H2O CPAP were applied to the airway opening via a modified Mapleson anesthesia circuit. Expiratory resistance (RL), midexpiratory tidal flow (VE50), and maximal flow at functional residual capacity (Vmax FRC) were compared at each level of CPAP. Vmax FRC increased threefold from baseline to 8 cm H2O CPAP (p < 0.005). In contrast, there was no difference in expiratory RL or in VE50 at any level of CPAP. These data suggest that in infants with acquired TBM, assessments of forced expiratory flow reflect the amount of CPAP necessary to prevent airway collapse during forced exhalation better than can measurements of tidal mechanics.

Airway Resistance↗

PubMed1992

Nonbronchoscopic approach to bronchoalveolar lavage in children with artificial airways.

Bronchoalveolar lavage (BAL) performed with a fiberoptic bronchoscope (FOB) is a useful method for sampling alveolar contents. Since the smallest FOB with a channel has a diameter of 3.6 mm, BAL is difficult to accomplish through artificial airways (AA) less than 5.0 mm I.D. We used a 4F balloon wedge pressure catheter to perform BAL through small AA. Supplemental O2 or ventilatory support was delivered via an adaptor through which the catheter was introduced. After it was passed distal to the AA, the balloon was inflated with normal saline (NS) to a predetermined volume, and advanced until resistance was felt. The balloon was deflated, advanced slightly, and then reinflated to achieve airway occlusion. Five aliquots of 0.75 mL/kg of NS were used for BAL. The procedure was performed in 20 children from 1 month (950 g) to 6 1/2 years of age (median, 9 months). All specimens contained abundant alveolar macrophages, indicating good recovery of alveolar contents. Clinically significant information was obtained in 17 (85%) cases, and no patient required an open lung biopsy. In conclusion, nonbronchoscopic bronchoalveolar lavage is a valuable method for obtaining alveolar contents in children with small AA that preclude the use of an FOB, and it obviates the need for open lung biopsy in many patients. This technique could be used as a research tool for measuring constituents of alveolar contents in infants and small animals.

Catheterization, Peripheral↗

PubMed1989

Purpuric rashes in cystic fibrosis.

Sixteen patients with cystic fibrosis experienced vasculitic rashes of the lower extremities that resembled hypergammaglobulinemic purpura. The rashes were associated with increased serum gammaglobulin G levels and rather severe lung disease. The rashes are probably the expression of chronic lung infection and high antigenic load in these patients. Their appearance was associated, in most cases, with poor long-term survival.

Adolescent↗

PubMed1983

Rhodotorula rubra peritonitis in patients undergoing continuous ambulatory peritoneal dialysis.

Although still uncommon, fungal peritonitis is being reported with increasing frequency in patients with renal failure who are undergoing long-term peritoneal dialysis. Although most cases have involved Candida albicans, other opportunistic pathogens have been reported as well. Recently, three patients were seen with serious peritoneal infections due to Rhodotorula rubra, a "nonpathogenic" fungus. In two patients, peritoneal fibrosis made further peritoneal dialysis impossible. The third patient died from complications of peritonitis. Environmental cultures revealed a possible common-source outbreak. Literature review reveals that infection due to this organism is most unusual and occurs only in the hospital setting in patients with serious compromise of host defenses.

Adolescent↗

PubMed1983

Serum thyroid hormone levels in patients on continuous ambulatory peritoneal dialysis and regular hemodialysis.

In vitro thyroid function tests were performed on clinically euthyroid patients undergoing regular hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). The mean serum total thyroxine (TT4) and total triiodothyronine (TT3) values measured before HD were significantly subnormal. Similarly, CAPD subjects had reduced TT3 concentrations with low normal TT4 levels. Free thyroxine measurements, estimated by two different methods were aberrant in CAPD patients. Low normal reverse triiodothyronine (rT3) values were found in HD, in contrast to high normal rT3 levels in CAPD. Thyroid stimulating hormone determinations were normal, corresponding with the euthyroid status in both patient groups.

Adult↗

PubMed1982

Acute sterile peritonitis.

We have encountered a sporadic form of aseptic peritonitis, not previously described, that we refer to as acute sterile peritonitis (ASP). This syndrome, which occurs with a frequency of 0.1% of dialyses, begins abruptly during peritoneal dialysis with abdominal pain, fever, and occasionally chills and vomiting. Coincident with the onset of symptoms, the dialysate return becomes cloudy with many white blood cells. Cultures are negative and resolution occurs within hours with continued dialysis. In this report we detail the clinical features of this new syndrome.

Acute Disease↗

PubMed1981

The effect of prostaglandin synthetase inhibitors on renal function: studies in normal rats during sodium or water diuresis and in rats with chronic renal insufficiency.

The effect of acute infusion of the prostaglandin synthetase inhibitors - meclofenamate or indomethacin - was examined in awake rats. Studies were performed in normal rats undergoing either sodium or water diuresis and in salt-replete rats with chronic renal insufficiency. Prostaglandin synthetase inhibitors had no effect on renal plasma flow, glomerular filtration rate or fractional excretion of sodium in any of the groups. Absolute urinary excretion rates for sodium and potassium decreased only in the normal, salt-replete rats. In contrast, prostaglandin synthetase inhibitors consistently decreased urinary flow and osmolar clearance under all experimental conditions studied. In the normal, salt-replete rats the fall in urine flow was preceded by an increase in urinary excretion of cyclic AMP. These results show that inhibitors of prostaglandin synthesis enhance the ability of the kidney to reabsorb water. This effect may be secondary to increased cyclic AMP generation and to increased urea recirculation resulting in higher urea accumulation in the renal medulla.

Animals↗

PubMed1978

Stimulation of adenylate cyclase in isolated rat glomeruli by prostaglandins.

The effect of prostaglandins and various agents on cyclic adenosine 3',5'-monophosphate generation was studied in isolated rat glomeruli. Specific activity of adenylate cyclase in the glomeruli showed a 12-fold increase over the crude homogenate and a fivefold increase over a tubular preparation. Prostacyclin (PGI2) preferentially stimulated adenylate cyclase of isolated glomeruli at a concentration as low as 10(-9) M. Prostaglandins (PGE1, PGE2, and PGA2) and parathyroid hormone (1-34 synthetic PTH fragment) increased adenylate cyclase in glomeruli with maximal stimulation at 2 X 10(-5) M and 2-4 microgram/ml, respectively. No inhibition of PGE2 on PTH stimulation was observed. Isoproterenol (2 X 10(-4) M) caused a small stimulation, while PGF2alpha, arginine vasopressin, and angiotensin II were ineffective. The presence of guanosine triphosphate in the adenylate cyclase assay enhanced basal and PGE2- and PTH-stimulated activity, but had no effect on NaF stimulation. These findings show an effect of prostaglandins and PTH on the glomerular cAMP system and raise the possibility of a physiological action of these agents on the glomerulus.

Adenylyl Cyclases↗

PubMedDate not supplied

Effect of oxygen on right ventricular performance evaluated by radionuclide angiography in two young patients with chronic lung disease.

Pulmonary hypertension is a relatively common complication of chronic lung disease in children that can cause diminished right ventricular performance (RVP) and, eventually, cor pulmonale and heart failure. Since oxygen may decrease pulmonary artery pressure in these patients, we questioned whether RVP would also improve concomitantly. We evaluated the effect of oxygen on RVP in two young hypoxemic patients by radionuclide angiography. A child with bronchopulmonary dysplasia and cor pulmonale who was not clinically in heart failure had acutely better RVP while breathing oxygen and a further improvement after continuous oxygen therapy for 1 year. In a young adult with cystic fibrosis who was suspected of being in heart failure RVP acutely improved when the FIO2 was increased. We conclude that oxygen may improve RVP in hypoxemic patients and speculate that the observation of such improvement may be valuable for the early detection of patients who can benefit from long-term oxygen therapy.

Adult↗